The study looked at how different types of nitrogen affect cherry tomatoes as they grow. They tested three types of nitrogen and found that a mix of 75% NO3- -N and 25% NH4+ -N helped the tomatoes grow bigger and accumulate more nitrogen. This mix also increased the activity of an enzyme called glutamine synthetase, which helps the tomatoes absorb nitrogen. The researchers found that the type of nitrogen used affected the tomatoes' nitrogen metabolism and gene expression, showing that the right balance can improve fruit development.